[FAB-16528] marbles private chaincode sync up

This CR is to port minor changes made in marbles
private in fabric/integration by FAB-15894 back
to fabric-samples.

Signed-off-by: Dongming <dongming@ibm.com>
Change-Id: I3d729f0d692dbd24e11c1cce45233eda5ddb4831

chaincode/marbles02_private/go/marbles_chaincode_private.go

@@ -199,18 +199,19 @@ func (t *SimpleChaincode) initMarble(stub shim.ChaincodeStubInterface, args []st
  return shim.Error("Error getting transient: " + err.Error())
  }
 
- if _, ok := transMap["marble"]; !ok {
+ marbleJsonBytes, ok := transMap["marble"]
+ if !ok {
  return shim.Error("marble must be a key in the transient map")
  }
 
- if len(transMap["marble"]) == 0 {
+ if len(marbleJsonBytes) == 0 {
  return shim.Error("marble value in the transient map must be a non-empty JSON string")
  }
 
  var marbleInput marbleTransientInput
- err = json.Unmarshal(transMap["marble"], &marbleInput)
+ err = json.Unmarshal(marbleJsonBytes, &marbleInput)
  if err != nil {
- return shim.Error("Failed to decode JSON of: " + string(transMap["marble"]))
+ return shim.Error("Failed to decode JSON of: " + string(marbleJsonBytes))
  }
 
  if len(marbleInput.Name) == 0 {
@@ -275,8 +276,8 @@ func (t *SimpleChaincode) initMarble(stub shim.ChaincodeStubInterface, args []st
  // ==== Index the marble to enable color-based range queries, e.g. return all blue marbles ====
  // An 'index' is a normal key/value entry in state.
  // The key is a composite key, with the elements that you want to range query on listed first.
- // In our case, the composite key is based on indexName~color~name.
- // This will enable very efficient state range queries based on composite keys matching indexName~color~*
+ // In our case, the composite key is based on indexName=color~name.
+ // This will enable very efficient state range queries based on composite keys matching indexName=color~*
  indexName := "color~name"
  colorNameIndexKey, err := stub.CreateCompositeKey(indexName, []string{marble.Color, marble.Name})
  if err != nil {
@@ -306,7 +307,7 @@ func (t *SimpleChaincode) readMarble(stub shim.ChaincodeStubInterface, args []st
  name = args[0]
  valAsbytes, err := stub.GetPrivateData("collectionMarbles", name) //get the marble from chaincode state
  if err != nil {
- jsonResp = "{\"Error\":\"Failed to get state for " + name + "\"}"
+ jsonResp = "{\"Error\":\"Failed to get state for " + name + ": " + err.Error() + "\"}"
  return shim.Error(jsonResp)
  } else if valAsbytes == nil {
  jsonResp = "{\"Error\":\"Marble does not exist: " + name + "\"}"
@@ -359,18 +360,19 @@ func (t *SimpleChaincode) delete(stub shim.ChaincodeStubInterface, args []string
  return shim.Error("Error getting transient: " + err.Error())
  }
 
- if _, ok := transMap["marble_delete"]; !ok {
+ marbleDeleteJsonBytes, ok := transMap["marble_delete"]
+ if !ok {
  return shim.Error("marble_delete must be a key in the transient map")
  }
 
- if len(transMap["marble_delete"]) == 0 {
+ if len(marbleDeleteJsonBytes) == 0 {
  return shim.Error("marble_delete value in the transient map must be a non-empty JSON string")
  }
 
  var marbleDeleteInput marbleDeleteTransientInput
- err = json.Unmarshal(transMap["marble_delete"], &marbleDeleteInput)
+ err = json.Unmarshal(marbleDeleteJsonBytes, &marbleDeleteInput)
  if err != nil {
- return shim.Error("Failed to decode JSON of: " + string(transMap["marble_delete"]))
+ return shim.Error("Failed to decode JSON of: " + string(marbleDeleteJsonBytes))
  }
 
  if len(marbleDeleteInput.Name) == 0 {
@@ -438,18 +440,19 @@ func (t *SimpleChaincode) transferMarble(stub shim.ChaincodeStubInterface, args
  return shim.Error("Error getting transient: " + err.Error())
  }
 
- if _, ok := transMap["marble_owner"]; !ok {
+ marbleOwnerJsonBytes, ok := transMap["marble_owner"]
+ if !ok {
  return shim.Error("marble_owner must be a key in the transient map")
  }
 
- if len(transMap["marble_owner"]) == 0 {
+ if len(marbleOwnerJsonBytes) == 0 {
  return shim.Error("marble_owner value in the transient map must be a non-empty JSON string")
  }
 
  var marbleTransferInput marbleTransferTransientInput
- err = json.Unmarshal(transMap["marble_owner"], &marbleTransferInput)
+ err = json.Unmarshal(marbleOwnerJsonBytes, &marbleTransferInput)
  if err != nil {
- return shim.Error("Failed to decode JSON of: " + string(transMap["marble_owner"]))
+ return shim.Error("Failed to decode JSON of: " + string(marbleOwnerJsonBytes))
  }
 
  if len(marbleTransferInput.Name) == 0 {